#include <stdio.h>
#include <string.h>
//int isPalindrome(char *str) {
int isPalindrome(char str[]) {
    int len = strlen(str);
    for (int i = 0; i < len / 2; i++) {
        if (str[i]!= str[len - i - 1]) {
            return 0;
        }
    }
    return 1;
}

int main() {
    char str[] = "ABCBA";
    int result = isPalindrome(str);
    if (result) {
        printf("%s is a palindrome string.\n", str);
    } else {
        printf("%s is not a palindrome string.\n", str);
    }
    return 0;
}